saut said:
Sounds like a flute synth at about 7:10 in GoP to me.
I'm pretty sure that's a mellotron (analogue to my ears?) with a flute tape.
The mellotron can cover a lot of the sounds you guys want to hear: strings, flute, choral, etc, etc. And it does a way better job than any overly digital sounding synths.
But yeah, I don't see the need for any more full time instruments/members. If there was a touch here or there (say, a cello or flute part in a song) I could just see a guest doing it, and simply for the part it was needed (ie: so they're not trying to find places to play all over the album). Most of the instruments I could see having 'guest appearances' would slot in nicely over the mellow moments; give them a distinct feel.
As for what types of instruments, mainly strings, or a flute (as I said, over ONE or TWO parts, not the whole album). Also possibly a more obscure instrument; a hurdy gurdy or some such. I could also see Per using a some really interesting vintage/antique organs, pianos, harpsichords, etc.
There's a lot of room to subtly experiment with soundscapes, but it needs to be done just right, and not in every moment of every track.